Statisticians use their knowledge of mathematics and statistical theory to collect and interpret information. They determine whether data are reliable and useful and search for facts that will help solve scientific questions.

Most statisticians work in one of three kinds of jobs: They may teach and do research at a large university, they may work in a government agency (such as the U.S. Census Bureau), or they may work in a business or industry. A few statisticians work in private consulting agencies and sell their services to industrial or government organizations. Other statisticians work in well-known public opinion research organizations. Their studies help us understand what groups of people think about major issues of the day or products on the market.

There are two major areas of statistics: mathematical statistics and applied statistics. Mathematical statisticians are primarily theoreticians. They develop and test new statistical methods and theories and devise new ways in which these methods can be applied. They also work on improving existing methods and formulas.

Applied statisticians apply existing theories or known formulas to make new predictions or discoveries. They may forecast population growth or economic conditions, estimate crop yield, predict and evaluate the result of a marketing program, or help engineers and scientists determine the best design for a jet airline.

In some cases, statisticians actually go out and gather the data to be analyzed. Usually, however, they receive data from individuals trained especially in research-gathering techniques. In the U.S. Census Bureau, for example, statisticians work with material that has been compiled by thousands of census takers. Once the census takers have gathered the data, they turn the information over to statisticians for organization, analysis, and conclusions or recommendations.

Statisticians are employed in many sectors of society. One of the largest employers of statisticians is the government, because many government operations depend on detailed estimates of activities. Government data on consumer prices, population trends, and employment patterns, for example, can affect public policy and social programs.

Statistical models and methods are also necessary for all types of scientific research. For example, a geoscientist estimating earthquake risks or ecologists measuring water quality both use statistical methods to determine the validity of their results. In business and industry, statistical theories are used to figure out how to streamline operations, optimize resources, and, as a result, generate higher profits. For instance, statisticians may predict demand for a product, check the quality of manufactured items, or manage investments.

The insurance industry also uses statisticians to calculate fair and competitive insurance rates and to forecast the risk of underwriting activities.

Statisticians who collect and study data for pharmaceutical companies, public health agencies, or hospitals are known as biostatisticians or biometricians. They use statistics to help study disease outbreaks, ascertain the effectiveness of medical treatments or drug trials, and perform analytical tasks that help their employers improve efficiency or reduce costs.